Elevator cable strain-equalizing connection



May 8, 1934.

W. P. FROST ELEVATOR CABLE STRAIN EQUALIZING CONNECTION Filed March 21, 1930 2 Sheets-Sheet l May 8, 1934. w p FROST 1,958,039

ELEVATOR CABLE STRAIN EQUALIZ ING CONNECTION Filed March 21, 1950 2 Sheets-Sheet 2 271% (E5 am KM Patented May 8, 1934 ATE UEE

ELEVATOR CABLE STRAIN-EQUALIZING C(PNNECTION Application March 21, 1930, Serial No. 437,684

Claims.

In passenger and freight elevators such as are used for transferring passengers and freight to and from different stories of high office buildings and other structures, the elevator cars are usually 5 suspended by a group of hoisting cables, about a half dozen, more or less, in number, which at the top engage parallel grooves in a hoisting pulley and are connected at their opposite end to a counterweight. It is obvious that as the positions of the car and counterweight change the weight of such portion of the hoisting cables as passes over the hoisting pulley will be transferred from one side to the other. The consequent variation is the relative weight suspended upon the car side and counterweight side of the system as the car rises and falls may be considerable, and the irregularity of operation due to this cause is objectionable, particularly in the case of very high buildings. To overcome this defect compensating cables, or in some instances chains have been employed, connected at opposite ends to the bottom of the car and to the counterweight and passing downwardly in a loop around a weighted pulley at the bottom of the elevator shaft, the weight per linear unit of the compensating cables being at least approximately equal to that of a similar length of the hoisting cables, so that the transfer in weight between the two vertical flights of the compensating cables balances that of the hoisting cables.

Owing to various causes, such as unequal size of pulley grooves, inequality in diameter of cables, unequal stretch of cables, use of new and partly worn cables in the same group, etc., it is 5 found that the tension of the different compensating cables varies more or less, resulting in unequal wear, looseness and swaying of part of the cables, noisiness in operation, irregularity in case the difference in tension brings about a sudden,

4O slight slippage of one of the cables, and in general a lack of smoothness and uniformity in the movement of the car. My present invention relates to improvements in elevator systems of the class described designed to remedy the defects mentioned through the introduction of a tension equalizing device connected to the compensating cables of the elevator system, and also relates to the particular construction of the equalizing device, separately considered and whether employed in connection with a group of compensating cables in the manner described, or employed in connection with a group of cables used for another purpose, or otherwise connected, as a group of cables for suspending an elevator car, or counterweight.

With the foregoing and incidental purposes in view 1' have designed and invented the equalizing connections for'elevators hereinafter particularly described, and my invention resides in the provision in' an elevator system of an equalizing device associated with the group of compensating cables, as described, andin the particular construction of the equalizing device, whereby it is adapted for such use, and further to the features of construction of such equalizing device which areof utility in other relations than that of connection with the compensating cables of an elevator system. In the appended claims I have more particularly'pointed out the essential elements of my invention, it being understood, however, that equivalent'eleinents and parts differing in particular construction from those illustrated and described may be substituted, and that I desire my claims construed to embrace all modifications and variations of construction falling within the true scope and spirit of my invention.

In the drawings,

Figure 1 is a side view on a small scale and diagrammatic in part, illustrating a typical elevator system in which my invention is shown embodied; Fig. 2 is a top plan view of the equalizing device alone, viewed below a plane indicated by the dotted line 22 of Fig. l;

Fig. 3 is' a vertical section of the same in a plane indicated'by the dotted line3+-3 of Fig. 2, the principal parts being shown in elevation; and parts of the front equalizing bar being broken away to disclose the construction of the yokes of which they form a part;

Fig. 4 is an end view of the equalizing device, looking from' the rear end forwardly, certain frame members being shown sectioned in a plane indicated by the dotted line li of Fig. 1;

Fig. 5 is a side view, corresponding in part to Fig. 3, illustrating the modified arrangement of certain parts when the device is used with an odd number of cables; and

Fig. 6 is a detail of certain. parts used in connection with the odd cable arrangement, viewed in a plane indicated by the dotted line 6-6 of Fig. 5.

Like reference characters indicate like part in all the figures of the drawings.

As shown in Figure 1, which illustrates a typical elevator system in which my invention is embodied, the elevator car 1 is suspended, preferably through an equalizing device represented generally by the reference character 2, by a group of hoisting cables 3, usually about six in number, which at one end are connected to the equalizing device and which at the top of the elevator shaft engage the grooves of the suspension pulley 4. 1

lil

This equalizing device may be similar in construc tion to that shown in Patent No. 1,606,158 or No. 1,429,070, both granted upon applications of Joseph E. Evans, or to that of the equalizing device hereinafter described in detail, in which certain specific features of my present invention reside. In electrically actuated elevator installations the hoisting pulley, as the pulley 4, is usually driven by an electric motor connected to it, and the power employed in raising and lowering the car is exerted through the pulley shaft. In some cases, though not in all, the hoisting cables pass from the hoisting pulley around an idler pulley 5 and then a second time around the pulley 4, as illustrated in the drawings. The other ends of the cables 3 are connected to a counterweight 6, either directly, as shown, or if preferred through a strain equalizing device, which may be similar in construction to the equalizing device 2 or of other suitable construction arranged to equalize the strain upon the cables. It will be understood that both the car and counterweight, in accordance with usual practice are guided in their vertical movements in the elevator shaft in which they both travel by suitable guide members.

The compensating cables, marked 7, of the elevator system illustrated are at one end connected to the bottom of the car by an equalizing device 8. to the specific construction of which certain features of my present invention relate, although in its broader aspect and considering the elevator system as a Whole, it will be understood that the specific construction in question is not essential. The compensating cables engage the grooves of a compensating pulley 9 which is journaled in and tensioned by a weight in the form of a heavy frame 10 slidably engaging vertical guide members 11 stationarily supported at the bottom of the elevator shaft, the pulley and connected frame floating in a downward loop of the compensating cables, and the other end of the compensating cables being secured to the counterweight 6.

As illustrated, and in accordance with well known practice, a striking block 12 is arranged at the bottom of the elevator shaft below the counterweight 6, and a buffer 13 is arranged below the car, a central oil buffer of suitable construction being indicated in outline.

The special form of equalizing device which I employ and which will now be described in detail is designed to occupy a minimum amount of space, measured vertically, whereby it is adapted to be used in elevator systems having a relatively shallow pit at the bottom. The portion of the compensating cables adjacent the car, moreover, preferably travel in a single vertical plane, as illustrated, and are consequently free from certain objections incident to equalizing devices in which the cables are attached in two spread groups to opposite ends of parallel equalizer bars, as in the case of the Evans patents above mentioned, due to the possibility of articles or obstructions of whatever nature falling in the elevator shaft below the car lodging between the spread cables and being carried downwardly to the compensating pulley and possibly forcing one or more of the cables out of their grooves. It will be understood, however, that my invention may be beneficially utilized with the compensat ing cables arranged to track in adjacent vertical paths in spread groups, or otherwise, instead of the preferred arrangement described and to which certain of the claims are limited.

The novel special form of equalizing device which I have devised for the purposes above explained includes a frame, the front end of which may conveniently be supported by a pair of channel members 14 forming part of an elevator car of well known construction, and which extend transversely across the car below the floor or platforms and are secured to the stiles 15 at opposite sides of the car. The two supporting bars 16 and 17 may be constructed of angle-iron, which are shown as bolted at their front ends to the underside of the two channel members 14. In case the stress on the com pensating cables is small this bolted connection may be an adequate support, but forgreater strength, I prefer to further support the rear end of the supporting bars by a cradle or brace consisting of a crossbar 18 secured to the supporting bars and connected by vertical rods 19 and 20 to the framework of the car.

The frame of the equalizing device further includes a pair of angle plates 21 and 22 having their horizontal portions arranged to rest upon and secured to the horizontal flanges of the supporting bars 14. Near their rear ends the two angle plates are connected by a transverse channel plate 24 which is secured to such angle plates by means of vertical rivet plates 25 and 26, the channel plate and rivet plates in the present instance extending somewhat below the level of the horizontal portions of the bars 14 and angle plates 21 and 22.

To the front ends of the channel plates 21 and 22 are severally secured vertical bearing plates 27 and 28 and preferably, the front ends of the channel plates are connected together and braced by a tie bar 29 passing through such plates and the bearing plates 27 and 28 near the upper forward corner of the connected parts.

Fitting in between the rearwardly extending flanges of the channel plate 24 is a bearing block 30 which sets obliquely in the channel so that the forward and rear faces are generally rhomboidal in outline. The bearing block is secured by screw bolts to the channel plate and is formed with two slots extending through it 7 from front to rear, to accommodate a pair of sheaves 31 and 32 which I will term equalizing sheaves, though the number of these may vary in accordance with the number of compensating cables used in the system. These sheaves are rotatably mounted on bearing pins seated in the bearing block and held in place by set screws, as illustrated,see Fig. 4, dotted lines.

The channel plate 24, it may here be noted, is orificed to accommodate loops of the equalizing cable 33 which extend horizontally and engage in alternation the equalizing sheaves and intermediate sheaves to be described later. This plate is also provided with two orifices, both of which,or in some cases, one only of which,- provide a ready means for equalizing cable.

The bearing plates 27 and 28 are orificed to receive a short bottom shaft 35, which may conveniently be restrained from disengagement by cotter pins near the opposite ends of the shaft; and such plates and the contiguous vertical portion of the angle plates 21 and 22 are similarly orificed to receive a top shaft 36 of similar construction and arrangement.

Rotatably mounted on the top shaft 36 are three guide sheaves 37, 38 and 39 forming an upper group, (see Fig. 2) and rotatably mounted on the bottom shaft 35 are three similar guide sheaves 40, 41 and 42, (see Fig. 4) forming a lower group, the sheaves of the two groups beanchoring said 5 ing arranged in staggered relation, so that a set of six equally spaced compensating cables '7 in a single vertical plane will track into the six sheaves. However, one object of my present invention is the provision of an equalizing device which by slight changes and adjustments can be used for a given even number of compensating cables, or an odd number one less than the even number, and I, therefore, contemplate the omission of one of the two outer guide sheaves and the use of but five cables, as will later be explained.

Describing the six-cable arrangement or the device, the intermediate sheaves before mentioned, marked 43, 44 and 45 (see Figs. 2 and 3) are mounted severally in three vertically disposed equalizing members in the form of floating yokes 46, 4'7 and 48 which each consist of a pair of equalizing bars a secured together in spaced relation by screws 49 engaging spacing sleeves 50 interposed between the bars a, see Fig. 3. Centrally of the pair of bars a a shouldered pivot pin 51 interposed between the bars provides a bearing for the associated sheave, while between the bars at each end of the yoke a cable-socket block 52 formed with trunnions pivoted in bearing orifices in the bars provides means for securing the upper end of one of the compensating cables '7, the ends of the cables which engage the top guide sheaves 37, 38

and 39 extending laterally towards the rear and being secured to the upper ends of the equalizing members or yokes 46, 47 and 48, respectively, while the ends of the cables which engage the lower guide sheaves 40, 41 and 42. extend laterally in a lower plane and are similarly connected to the lower ends of such yokes respectively.

The equalizing cable 33 is anchored at one end, as by an ordinary thimble block, to the channel plate 24 in horizontal alignment with the lowermost portion of the groove of the intermediate sheave 45, and in succession engages such sheave and the sheaves 32, 44, 31 and 43,

the other end of the equalizing cable being anchored to the plate 24 opposite the top of the groove of the intermediate pulley 43,see Figs. 2 and 3.

It is obvious that the weight of the compen- .5 vsating pulley and connected frame, which in practice usually amounts to about fifteen hundred pounds, more or less, will exert a pull upon the compensating cables, and exert a steadying effect, and by reason of the action of the equal- .izing device the strain upon the cables will be completely equalized, and no one cable will be slack and capable of swinging or flapping about to cause noise or set up any vibration and disturb the smooth operation of the car. All the cables track at all times in a strictly vertical path, which in itself conduces to smoothness and quietness of operation as compared with cables which spread away from each other to a connection with horizontal equalizing bars and continually change the angle at which they stand as the car ascends and descends.

It is further obvious that the equalizing devices employed in the elevator apparatus described will serve at all times to equalize perfectly the strains upon the hoisting and compensating cables, and inasmuch as no springs or other resilient equalizing members are employed in the equalizing devices there can be no tendency of the car to spring or bounce from spring action when the car is stopped or started, as in the case of cer- 'tain forms of connecting devices known in the art in which the cables are severally connected to the car (or counterweight) by interposed springs, which have the effect of tensioning the cables unequally and also exhibit a resilient spring action which is manifested at any change in movement of the car.

If, as may sometimes be the case, it is desired to install five compensating cables, the equalizing device shown may be arranged and adapted to such a system with scarcely any change, by omitting one of the outermost or end guide sheaves, as the sheave 42 of the lower group, the space on the bottom shaft occupied by it being filled by a spacing block, and also omitting the intermediate sheave 45, and connecting the com pensating cable which engages the sheave 39 of the other or upper group of guide sheaves'directly with the equalizing cable running from the top of the equalizing sheave 32, the arrangement of the sheaves 39 and 32 being such that the connected equalizing and compensating cables will track in alignment in the grooves of the two sheaves. Obviously, asimilar change may be made by orntting the guide sheave 37 and intermediate sheave 43,.and connecting the equalizer cable with the compensating cable running in the guide pulley 40.

To facilitate the connection of the equalizing and compensating cables I have provided a split rope coupling which consists of blocks 53 and 54 adapted to be bolted together and formed with matching grooves which are adapted to receive and provide an anchorage for the ends severally of the equalizing cable and the particular compensating cable. Also to ensure smooth movement of the stretch of connected cable ends between the sheaves 39 and 32 and obviate any possibility that a twisting of the connected cable ends might bring about interference of the coupling blocks with the adjacent yoke 47, I have provided the member 54 of the rope coupling with a pair of ribs 55 arranged to seat over a guide plate 56 secured to the adjacent angle plate 22.

It is obvious that by inverting the equalizing device as a whole,-i. e., turning it upside down from the position shown in Fig. 3,it may be used as a suspension device, the upwardly extending cables in such case being hoisting cables.

I claim:

1. A strain-equalizing device for connecting an elevator car or the like to a plurality of parallel cables running in a single vertical plane and subject to joint strain, said device comprising a corresponding number of guide sheaves arranged to severally engage said cables, the ends of said cables extending laterally from said guide sheaves, a plurality of equalizing sheaves, a plurality of floating intermediate sheaves having separate bearing pins connected to said first mentioned cables, and an equalizing cable extending in laterally disposed loops around said equalizing sheaves and said intermediate sheaves.

2. A strain-equalizing device for connecting an elevator car or the like to a plurality of parallel cables running in a single vertical plane and subject to joint strain, said device comprising a corresponding number of guide sheaves arranged to severally engage said cables, said guide sheaves being arranged in upper and lower groups in staggered relation and the ends of the cables extending laterally from the sheaves in two groups at different heights, a plurality of vertically disposed floating yokes connected each at top and bottom severally with the ends of two adjacent cables, a plurality of intermediate sheaves pivoted severally in said yokes, a plu rality of equalizing sheaves, and an equalizing cable extending in laterally disposed loops around said equalizing sheaves and said intermediate sheaves.

3. A strain-equalizing device for connecting an elevator car, or the like, to an even plurality of parallel cables running in a single vertical plane and subject to joint strain, said device comprising a corresponding number of guide sheaves arranged to severally engage said cables and said sheaves being arranged in equal upper and lower groups in staggered relation and the ends of the cables extending laterally from the sheaves in two groups at different heights, a plurality of vertically disposed floating yokes one-half in number to the number of said cables and guide sheaves, each yoke being connected at top and bottom severally with the ends of two adjacent cables, a plurality of intermediate sheaves pivoted severally in said yokes, a plurality of equalizing sheaves one less in number than said intermediate sheaves, and an equalizing cable anchored to the car at both ends and extending in laterally disposed loops around said equalizing sheaves and said intermediate sheaves.

4. A strain equalizing device according to claim 3 in which an outermost guide sheave of one group is removable and a cable in the groove of the adjacent guide sheave of the other group is arranged to track into the groove of the equalizing sheave on the same side of the device, and in which said equalizing cable is adapted to be connected with the cable running in said aligned guide sheave.

5.. A strain-equalizing device for connecting an elevator car or the like to a plurality of cables arranged to track in adjacent vertical paths and subject to joint strain, said device comprising a corresponding number of guide sheaves arranged to severally engage said cables, the ends of said cables extending laterally from said guide sheaves, a plurality of equalizing sheaves, a plurality of floating intermediate sheaves having separate bearing pins connected to said first mentioned cables, and an equalizing cable extending in lat-p erally disposed loops around said equalizing sheaves and said intermediate sheaves.

WILLIAM P. FROST. 

